Lacking population-specific data, activity of seasonal and pandemic influenza is usually tracked by counting the number of diagnoses and visits to medical facilities above a baseline. This type of data does not address the delivery of services in a specific population. To provide population-specific data, this retrospective study of patients with influenza-like illness, influenza, and pneumonia among members of a Kaiser Permanente health plan in San Diego, California, USA, during October-December 2009 was initiated. Population data included the number of outpatients accessing healthcare; the number of patients diagnosed with pneumonia; antimicrobial therapy administered; number of patients hospitalized with influenza, influenza-like illness, or pneumonia; level of care provided; and number of patients requiring specialized treatments (e.g., oxygen, ventilation, vasopressors). The rate of admissions specific to weeks and predictions of 2 epidemiologic models shows the strengths and weaknesses of those tools. Data collected in this study may improve planning for influenza pandemics.
Keywords: 2009; H1N1; Influenza A virus; ambulatory care; anti-infective agents; antimicrobial; antiviral; health planning; healthcare delivery; hospitalization; influenza A(H1N1)pdm09; inpatients; intensive care units; oseltamivir; pandemic; pandemics; pdm2009; pneumonia; population dynamics; population-based planning; positive pressure respiration; telemetry; vasoconstrictor; ventilation; viruses.